Jamie Campbell Bower has appeared in Harry Potter and Twilight, but The Mortal Instruments: City Of Bones will be his big break. Starring as troubled heartthrob Jace Wayland, Bower’s not sure he’s ready for the kind of fame that Robert Pattinson or Daniel Radcliffe were met with.

“The whole fame aspect of acting makes me feel a bit… not nervous, but it’s just not something I’m really into,” he says. “I try not to think about it. I am not doing this to be famous, I am doing this because I love what I do.”

It’s a good job, since this demon-slaying role has meant getting up at unsociable hours to work on his bod. “The physical element was pretty hardcore for me, being a) English and b) early 20s, the last thing you want to do is get up in the morning and go to the sodding gym,” he admits. “I was doing maybe three hours of training every day and having to change my diet and having to constantly be like, ‘I can’t have a sandwich. I can’t even look at wheat.’”

The regime is all part of his sexy new look that will turn Clary (Lily Collins)’s head in the film, but to her best friend Simon’s annoyance. If you dig his hoody, though, Bower wants you to know it was all his idea. “We started off with a lot of long coats, a lot of quite bondage-y looking stuff, and that was cool but I was like, ‘Yeah, but it’s getting a bit Matrix-y here maybe.’ So we ended up going with a more biker-boy look, then we went through leather jackets and I was like, ‘It would be great if I had a hood, to add that element of mystery.’ A hood is always brilliant for mystery. People love hoods.”

Whether fans love the film remains to be seen, but it’s not too long to wait now! If it performs at the box office as well as other YA novel adaptations, the filmmakers have plenty of material to draw from – there’s six books altogether!